JP3149065U - Camshaft - Google Patents

Abstract

Provided is a camshaft that can be molded with high accuracy without material loss, can be easily positioned and assembled with a shaft, and can be reduced in weight at low cost. A large-diameter portion 2a formed at one end and a fitting shaft portion 2b having a smaller diameter than the large-diameter portion 2a and having a dodecagonal cross section extending from the large-diameter portion 2a to the other end are integrally formed, and the central portion A hollow shaft 2 formed with a dodecagonal cross-section fitting hole 2d into which a fitting shaft portion 2b can be fitted is formed at one end thereof, and can be fitted into the fitting shaft portion 2b. The cam piece 3 is formed with a through hole 3a having a dodecagonal cross section, and the spacer 4 is formed with a through hole 4a having a polygonal cross section having 12 or more corners that can be fitted to the fitting shaft portion 2b or an involute. The cam piece 3 and the spacer 4 are fitted to the fitting shaft portion 2b of the hollow shaft 2 from the other end, and the cam piece 3 and the spacer 4 are integrally fixed to the fitting shaft portion 2b. [Selection] Figure 1

Description

  The present invention relates to a camshaft used to open and close intake and exhaust valves in an engine.

  Conventionally, as this type of camshaft, for example, a solid shaft and a cam that are integrally formed by forging or casting are known.

  However, if the solid shaft and cam are integrally formed by forging or casting, the structure is complex and high-precision molding is difficult, so polishing and finishing of the solid shaft and cam are difficult. It is complicated and laborious, and forging or casting has a lot of material loss. In addition, it is solid and requires a large amount of material, resulting in a high cost and a heavy weight. Had.

  Therefore, in the present invention, the camshaft is composed of three parts, each of which is cold-molded by a part former, so that it can be molded with high accuracy without any material loss, and can be reduced in weight at a low cost. It is an object of the present invention to provide a camshaft which can be easily and easily aligned and assembled with respect to the camshaft and can be used as a long camshaft if necessary.

In order to solve the above-described problems, the present invention has a large-diameter portion 2a formed at one end and a polygonal cross-section or involute shape having a diameter smaller than that of the large-diameter portion 2a from the large-diameter portion 2a to the other end and 12 corners or more. The fitting shaft portion 2b to be presented is integrally formed, and has a through-hole 2c at the center and a polygonal cross section or involute shape having 12 or more corners into which the fitting shaft portion 2b can be fitted to one end of the through-hole 2c. A hollow shaft 2 in which a fitting hole 2d is formed, a cam piece 3 in which a through hole 3a having a polygonal cross section or an involute shape of 12 or more corners that can be fitted to the fitting shaft 2b is formed; And a spacer 4 having a through-hole 4a having a polygonal cross section or an involute shape having 12 or more corners that can be fitted to the fitting shaft portion 2b. The hollow shaft 2, the cam piece 3, and the spacer 4 are respectively formed as part parts. On the other hand, the cam piece 3 and the spacer 4 are fitted from the other end to the fitting shaft portion 2b of the hollow shaft 2, and the cam piece 3 and the spacer 4 are fitted to the fitting shaft portion 2b. Is fixed integrally.
Involute is a concept including splines and serrations with fine pitches.

  According to the camshaft of the present invention, the camshaft 1 is composed of the three parts of the hollow shaft 2, the cam piece 3, and the spacer 4 as described above, and each of them is cold formed by a parts former so that there is no material loss. The camshaft can be formed with high precision and the entire camshaft can be reduced in weight because the shaft is hollow, and the material can be reduced and the cost can be reduced. Moreover, since the cam 3 is non-rotatably attached to the hollow shaft 2 by fitting the fitting shaft portion 2b of the hollow shaft 2 having, for example, a dodecagonal section and the through hole 3a of the cam 3 having a dodecagonal section, When the plurality of cams 3 are provided on the hollow shaft 2, angle setting and angle change with respect to the circumferential direction of each cam 3, 3 can be easily and easily performed. Furthermore, since the fitting hole part in which the fitting shaft part 2b can be fitted is formed in the large diameter part 2a of the hollow shaft 2, the fitting hole part 2d of the hollow shaft 2 in one set is By fitting the tips of the fitting shaft portions 2b of the other set of hollow shafts 2, a necessary number of them can be connected and used as a long camshaft.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 and 2 show a camshaft according to the present invention. The camshaft 1 has a large-diameter portion 2a formed at one end as shown in FIGS. 3 and 4, and extends from the large-diameter portion 2a to the other end. A fitting shaft 2b having a smaller diameter than the large-diameter portion 2a and having a dodecagonal cross section is integrally formed, and the through-hole 2c can be fitted to one end of the through-hole 2c at the center. A hollow shaft 2 formed with a fitting hole 2d having a dodecagonal cross section and a through hole 3a having a dodecagonal cross section that can be fitted to the fitting shaft 2b as shown in FIGS. As shown in FIGS. 7 and 8, the cam piece 3 is formed, and the spacer 4 is formed with a through hole 4a having a dodecagonal cross section that can be fitted to the fitting shaft portion 2b. The hollow shaft 2, the cam piece 3, and the spacer 4 are each formed with high accuracy without material loss by being cold formed by a parts former.

  When assembling, the cam pieces 3 and 3 and the spacer 4 are alternately fitted to the outer periphery of the fitting shaft portion 2b of the hollow shaft 2 as shown in FIGS. In that case, the fitting positions in the circumferential direction between the through holes 4a and 4a of the cam pieces 3 and 3 and the fitting shaft portion 2b of the hollow shaft 2 are respectively selected to provide a predetermined phase difference and then fitted. Set. Here, the length of the fitting shaft portion 2b of the hollow shaft 2 is set so that the tip of the fitting shaft portion 2b of the hollow shaft 2 protrudes a predetermined length outward from the outer cam piece 3.

  Thereafter, the cam piece 3 and the spacer 4 are integrally fixed to the fitting shaft portion 2b by caulking. In that case, in addition to caulking and fixing all the cam pieces 3 and 3 and the spacer 4, for example, only the cam piece 3 positioned at the extreme end opposite to the large-diameter portion 2 a of the hollow shaft 2 is caulked. It may be.

  The fixing means is not limited to caulking and may be appropriate fixing means such as welding, keying, or bolting. If appropriate fixing means such as keying or bolting are used, the cam piece 3 and the spacer 4 can be repeatedly attached to and detached from the fitting shaft portion 2b. Changes can be made arbitrarily.

  In use, as shown by phantom lines in FIGS. 1 and 2, the driving shaft 5 in a transmission mechanism such as a chain or gear is connected to the tip of the fitting shaft portion 2b of the hollow shaft 2 by fitting. It is done. In that case, the large diameter part 2a of the hollow shaft 2 and the connecting large diameter part 5a of the drive shaft 5 are used as a journal.

  In the embodiment shown in the figure, the fitting shaft portion 2b of the hollow shaft 2, the fitting hole portion 2d, the through hole 3a of the cam piece 3, and the through hole 4a of the spacer 4 are each a dodecagonal cross section. For example, although not shown, it may be a polygonal cross section having a dodecagonal cross section or more, or may be an involute, fine pitch, spline or serration.

  In the drawings, only one set in which two cam pieces 3 and 3 and one spacer 4 are combined in one hollow shaft 2 has been described. However, a plurality of sets are connected in series in the axial direction and are long. It can also be used as a scale camshaft. That is, when the two cam pieces 3 and 3 and one spacer 4 are set in combination on the hollow shaft 2, the end of the fitting shaft portion 2 b is hollow so as to protrude outward by a predetermined length from the outer cam piece 3. While the length of the fitting shaft portion 2b of the shaft 2 is set, the large diameter portion 2a of the hollow shaft 2 is formed with a fitting hole portion into which the fitting shaft portion 2b can be fitted. By fitting the tip of the fitting shaft portion 2b of the other set of hollow shafts 2 into the fitting hole portion 2d of the hollow shaft 2, it is possible to connect as many as necessary. In that case, what is necessary is just to fix the hollow shafts 2 ... 2 by welding etc. as needed.

  As described above, according to the camshaft 1 of the present invention, the camshaft 1 is composed of three parts, that is, the hollow shaft 2, the cam piece 3, and the spacer 4, and each is cold-formed by a parts former, It can be formed with high accuracy without loss, and the entire shaft 2 can be reduced in weight because the shaft 2 is hollow, and the material can be reduced and the cost can be reduced. Moreover, since the cam 3 is non-rotatably attached to the hollow shaft 2 by fitting the fitting shaft portion 2b of the hollow shaft 2 having, for example, a dodecagonal section and the through hole 3a of the cam 3 having a dodecagonal section, When the plurality of cams 3 are provided on the hollow shaft 2, the angle setting with respect to the circumferential direction of each of the cams 3 and 3 and the angle change thereof can be easily and easily performed. Further, since the fitting hole portion 2d into which the fitting shaft portion 2b can be fitted is formed in the large-diameter portion 2a of the hollow shaft 2, the fitting hole portion 2d of one set of the hollow shafts 2 has the other fitting hole portion 2d. By fitting the tips of the fitting shaft portions 2b of the pair of hollow shafts 2, a necessary number of them can be connected and used as a long camshaft.

  It is a longitudinal cross-sectional view of the camshaft which concerns on this invention.   It is a front view of the camshaft.   It is a front view of a hollow shaft.   It is the same side view.   It is a side view of a cam.   It is a front view of the cam.   It is a side view of a spacer.   It is a front view of the spacer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cam shaft 2 Hollow shaft 2a Large diameter part 2b Fitting shaft part 2c Through hole 2d Fitting hole part 3 Cam piece 3a Through hole 4 Spacer 4a Through hole

Claims (1)

  A large-diameter portion 2a formed at one end and a fitting shaft portion 2b having a polygonal cross-section or involute shape having a diameter smaller than that of the large-diameter portion 2a and extending from the large-diameter portion 2a to the other end are formed integrally. A hollow formed by forming a through hole 2c at the center and a fitting hole 2d having a polygonal cross section or an involute shape having 12 or more corners into which the fitting shaft 2b can be fitted at one end of the through hole 2c. The shaft 2, the cam piece 3 in which the through-holes 3a having a polygonal cross section or involute shape of 12 or more corners that can be fitted to the fitting shaft portion 2b are formed, and the 12 corners that can be fitted to the fitting shaft portion 2b The hollow shaft 2, the cam piece 3, and the spacer 4 are each formed by cold forming with a part former while the hollow shaft 2 is formed. The cam piece 3 and the spacer 4 are fitted from the other end to the fitting shaft portion 2b of the shaft 2, and the cam piece 3 and the spacer 4 are integrally fixed to the fitting shaft portion 2b. Camshaft.

Images